Cat questions
Thread Starter
Senior Member
Joined: Aug 2001
Posts: 814
Likes: 2
From: San Jose, CA, USA
Car: 88 IROC-Z - original owner!
Engine: LB9 with K&Ns, MSD, Foil, Taylor
Transmission: WC T-5
Axle/Gears: BW 9-bolt, 3.45 posi
Cat questions
I've seen a few guys complaining that they had to replace their Cats because it was "clogged".
1. - What causes a Cat to clog, and what is the normal expected lifespan of a Cat?
I have an 88 IROC with the 305/TPI and the stock Cat.
2. - Would I notice much difference in performance or gas milage if I replaced it with a hi-flow Cat?
3. - Are the aftermarket hi-flow Cats complete bolt-on replacements with no other mods required? (My cat has an air pipe also).
4. - Are these aftermarket hi-flow Cats smog legal in California?
5. - Would I also notice much difference if I replaced the stock muffler with a Flowmaster 80 series?
Thanks!
1. - What causes a Cat to clog, and what is the normal expected lifespan of a Cat?
I have an 88 IROC with the 305/TPI and the stock Cat.
2. - Would I notice much difference in performance or gas milage if I replaced it with a hi-flow Cat?
3. - Are the aftermarket hi-flow Cats complete bolt-on replacements with no other mods required? (My cat has an air pipe also).
4. - Are these aftermarket hi-flow Cats smog legal in California?
5. - Would I also notice much difference if I replaced the stock muffler with a Flowmaster 80 series?
Thanks!
Supreme Member
Joined: Apr 2001
Posts: 1,516
Likes: 1
From: St. Catharines, ON
Yes, a new cat will probably help a little in the horsepower department. A loss of restriction might lose some torque, but we're talking fractions of percentages.
You probably won't notice the difference if you do the cat alone. Get a 3" cat back along with it, and you'll see results.
I think that you sometimes need to justify removing the old cat and replacing it. Doing it on a brand new car might not be so kosher. Our cars are old enough that its not that big of a deal (even in ****-retentive Cali).
Good names are Random Technologies (muy $$$), and Catco (way less expensive).
As for bolt-onability, it depends on the application/part. Talk to the manufacturers.
------------------
No guts, no glory.
You probably won't notice the difference if you do the cat alone. Get a 3" cat back along with it, and you'll see results.
I think that you sometimes need to justify removing the old cat and replacing it. Doing it on a brand new car might not be so kosher. Our cars are old enough that its not that big of a deal (even in ****-retentive Cali).
Good names are Random Technologies (muy $$$), and Catco (way less expensive).
As for bolt-onability, it depends on the application/part. Talk to the manufacturers.
------------------
No guts, no glory.
Joined: Mar 2000
Posts: 43,187
Likes: 42
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
With regard to #1 "the normal expected lifespan of a cat":
The replacement cat I got for my van had a card in it that I was supposed to send in to a "clearing house". It said something to the effect that a catalytic convertor does not normally wear out, so the vehicle owner had to sign indicating they understood that, and the replacing shop had to fill in exactly why the cat was being replaced (damaged, removed, etc.). "Worn out" was not a choice for reasons to replace.
FWIW, my original pancake cat was empty of all catalyst material (I think I put "worn out" in the "Other" space). Passed emissions testing much easier with that "universal replacement" (which did include an A.I.R. pipe). You shouldn't have any trouble passing CA smog with a replacement high-flow cat.
------------------
82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. 2-1/2" cat-back, ZZ3 intake, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam, ported World 305 heads, Hooker 2055 headers, 3" Catco cat & 3" cat-back, Spohn SFCs).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).
The replacement cat I got for my van had a card in it that I was supposed to send in to a "clearing house". It said something to the effect that a catalytic convertor does not normally wear out, so the vehicle owner had to sign indicating they understood that, and the replacing shop had to fill in exactly why the cat was being replaced (damaged, removed, etc.). "Worn out" was not a choice for reasons to replace.
FWIW, my original pancake cat was empty of all catalyst material (I think I put "worn out" in the "Other" space). Passed emissions testing much easier with that "universal replacement" (which did include an A.I.R. pipe). You shouldn't have any trouble passing CA smog with a replacement high-flow cat.
------------------
82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. 2-1/2" cat-back, ZZ3 intake, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam, ported World 305 heads, Hooker 2055 headers, 3" Catco cat & 3" cat-back, Spohn SFCs).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).
Thread
Thread Starter
Forum
Replies
Last Post